3D Trig to show my basic module for the Pentagon Thingammy has hexagon holes with alternate angles of 108 and 130. A planar hexagon would have pairs totalling 240 but these total 238.4 It is therefore a non-planar hexagon and is known to chemists as a 'puckered hexagon in a chair formation' If you google this then it takes you into a number of references to inorganic chemistry and links to types of Ice (type I), or Diamond or Cyclohexane. The planar form links to benzene. My friend(a chemist) says this is cutting edge technology. Chemists it seems are the people to go to when discussing 3D geometry.